Lubricant for recycle gas compressor employed in hydroforming systems



LUBRICANT FOR RECYCLE GAS COMPRESSOR EMPLOYED IN HYDROFORMING SYSTEMS William P. Hilliker, New Orleans, La., and Harry K.

Wheeler, El Dorado, Ark., assignors, by mesne assignments, to The American Oil Company, a corporation of Maryland No Drawing. Application May 9, 1955 Serial No. 507,117

2 Claims. (Cl. 252-56) This invention relates to the lubrication of gas compressors employed in catalytic conversion processes and it pertains more particularly to an improved lubricant for recycle gas compressors in naphtha hydroforming units employing supported platinum catalysts.

The many known types of naphtha hydroforming processes employing supported platinum catalysts such, for

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tion properties of the polybutene by reducing wear and example, as Platforming, Catforming, Houdriforming, v

Ultraforming, etc., all require the use of gas compressors for circulating a recycled hydrogen stream from a hydrogen separator to a reheater and thence to a bed of supported platinum catalyst. Difliculties have arisen in such systems because hydrocarbon oil employed as compressor lubricant is picked up in varying amounts with the recycled gas stream and ultimately becomes deposited on the supported platinum catalyst thus leading to the formation of carbonaceous deposits thereon which not only tend to deactivate the catalyst but which cause increase in pressure drop across the reactor or, in other words, tend to plug the catalyst bed with deposits. The object of this invention is to provide an improved method and means for avoiding such difliculties. A specific object of the invention is to provide an improved lubricant for the cylinders of gas compressors employed in catalytic conversion processes wherein the presence of ordinary mineral lubricants is detrimental. Other objects will be apparent from the following detailed description.

In accordance with our invention the cylinders of recycle gas compressors employed in hydroforming units are continuously lubricated with a mixture of butylene polymers of lubricating oil viscosity containing a small amount, not substantially exceeding about 1 percent, of a lubricity oiliness agent such, for example, as sperm oil.

The mixture of butylene polymers is preferably of relatively narrow molecular weight range, i. e. substantially free from light polymers having viscosities below 100 seconds Saybolt at 100 F. and substantially free from heavy polymers having viscosities upwards of 1,000 seconds Saybolt at 210 F. The preferred polybutene lubri cant is one having a viscosity in the range of about to 90 seconds Saybolt at 210 F. A polybutene of such viscosity may, however, be obtained by blending butylene polymers having an average viscosity of about 100 seconds at 100 F. with heavy polymers having an average viscosity of about 1,000 seconds at 210 F. The pre substantially eliminating valve deposits and, at the same time, its presence in the lubricant in the defined amounts does not cause catalyst deactivationand carbon formation which would be caused by the use of ordinary mineral lubricating oils in the lubricant composition.

-While sperm oil is our preferred lubricity oiliness agent, it should be understood that other stable, non-carbonforming oiliness agents of this general type may be employed in its stead. The preferred class of such, agents is that of fatty materials such as lard oil, seal oil, cottonseed oil and the like, although other polar oiliness agents known to the art may be employed provided that they have no detrimental effect on coking tendencies and catalyst deactivation in the catalyst bed of the hydroforming unit. The fatty materials may be acids such as oleic, stearic acid, and the like, or they may be esters, particularly glyceride esters. They should, of course, be non-drying.

As a specific example of our invention a mixture of polybutene polymers of lubricating oil viscosity, said mixture having a viscosity of about 65 seconds Saybolt at 210 F., was blended by conventional mixing with about 1 percent by weight of sperm oil. The lubricant thus formulated Was employed to lubricate the cylinders of a Clark 440 H. P. HRA gas engine driven compressor in a commercial Ultraforming unit for a period of over nine months. During this entire period the compressor lubrication has been remarkably effective, there has been no coke formation in the catalyst beds caused by lubricating oil carried thereto in recycled gases and catalyst deactivation from this source has thus been entirely eliminated.

Other examples of compressor lubricants within the scope of our invention are:

1) A mixture of butylene polymers having a viscosity of seconds Saybolt at 210 F. and containing .1 percent oleic acid,

(2) A mixture of butylene polymers having a viscosity of 40 seconds Saybolt at 210 F. containing about 1 percent lard oil, 7

(3) A mixture of butylene polymers having a viscosity of about 66 seconds Saybolt at 210 F. containing about .5 percent'sperm oil, and

(4) A mixture of butylene polymers having a viscosity of about 50 seconds Saybolt at 210 F. and containing about 1 percent of cottonseed oil.

Other examples will be apparent from the above description to those skilled in the art.

We claim:

1. In a naphtha hydroforming system wherein a lubricated gas compressor recycles a hydrogen gas stream to a hydroforming reactor containing a platinum-on-alumina catalyst, said catalyst gradually having carbonaceous deposits formed thereon during the hydroforming of the naphtha, the improvement whereby the formation of car bonaceous deposits on the catalyst due to coking thereon of compressor lubricant carried off by the recycle hydrogen gas is reduced which improvement comprises lubricating said compressor with a lubricant consisting of a mixture of butylene polymers ranging in viscosity.

from about seconds Saybolt at 100 F. to 1000 seconds Saybolt at 210 F. which mixture has a viscosity in the range of about 50 to 90 seconds Saybolt at 210 F.

(References on following page) llefmnces Cited in the file of this patent OTHER REFERENCES Ind. and Eng. Chem., vol. 23, No. 6, pages 604-611. UNITED STATES PATENTS Motor Oils and Engine Lubrication, by Georgi, Rein- 627,278 Nelson June 20, 1899 hold Pub. Co., 1950, pages 219 and 220.

' 1,869,779 Roberts Aug. 2, 1932 5 Uses and Applications of Chemicals and Related Materials, by Gregory, Reinhold Pub. Co., 1939, page 567. 

1. IN A NAPHTHA HYDROFORMING SYSTEM WHEREIN A LUBRICATED GAS COMPRESSOR RECYCLES A HYDROGEN GAS STREAM TO A HYDROFORMING REACTOR CONTAINING A PLATINUM-ON-ALUMINA CATALYST, SAID CATALYST GRADUALLY HAVING CARBONACEOUS DEPOSITS FORMED THEREON DURING THE HYDROFORMING OF THE NAPHTHA, THE IMPROVEMENT WHEREBY THE FORMATION OF CARBONACEOUS DEPOSITS ON THE CATALYST DUE TO COKING THEREON OF COMPRESSOR LUBRICANT CARRIED OFF BY THE RECYCLE HYDROGEN GAS IS REDUCED WHICH IMPROVEMENT COMPRISES LUBRICATING SAID COMPRESSOR WITH A LUBRICANT CONSISTING OF A MIXTURE OF BUTYLENE POLYMERS RANGING IN VISCOSITY FROM ABOUT 100 SECONDS SAYBOLT AT 100*F. TO 1000 SECONDS SAYBOLT AT 210*F. WHICH MIXTURE HAS A VISCOSITY IN THE RANGE OF ABOUT 50 TO 90 SECONDS SAYBOLT AT 210*F. AND A SMALL AMOUNT NOT SUBSTANTIALLY EXCEEDING ABOUT 1 PERCENT BY WEIGHT OF A FATTY MATERIAL WHICH SERVES AS A LUBRICITY OILINESS AGENT. 